Spring urged ignitable actuating element



United States Patent Field of Search lnventors Reinhold Rapp Stadeln; Heinz Gawlick, Furth; Hellmut Bendler, Nurnberg, Germany 'Appl. No 719,652

Filed April 8, 1968 Patented Nov. 24, 1970 Assignee Dynamit Nobel Aktiengesellschaft Troisdorf, Germany Priority April 7, 1967 Germany No. D 52735 SPRING URGED IGNITABLE ACTUATING ELEMENT 7 Claims, 5 Drawing Figs.

U.S. Cl 89/1; 60/261, 185/37 Int. Cl F0lb 29/08 102/31;

[56] References Cited UNITED STATES PATENTS 2,485,921 10/1949 Rockwell 89/l.01 2,557,448 6/1951 Mathisen... 137/76X 2,994,563 8/1961 Ruggiero 60/26.1X 3,063,515 11/1962 Williamson... 60/26.]X 3,097,902 7/1963 Hennessey.... 89/1 .01X 3,265,408 8/1966 Dickie 89/1.01X 3,334,204 8/1967 Brenny et a1... 200/82 3,393,605 7/1968 Parnell 89/1.01

Primary Examiner-Robert F. Stahl Attorney-Craig, Antonelli, Stewart & Hill ABSTRACT: The translating actuating member of the element is held against the bias of a spring by a member that will release it in response to the heat given off by an electrically actuated pyrotechnic charge. The member may be a metallic plate or wire meltable or deformable in response to the heat given off by the pyrotechnic charge or a ring spring radially expansible in response to the heat.

Patented Nov. 24, 1970 Sheet l INVENTORS REINHOLD RAPP HEINZ GAWLICK HELLMUT BENDLER Patented Nov. 24, 1970 Sheet lu rr INVENTORS I90 msmnow RAPP HEINZ GAWLICK BY HELLMUT BENDLER M A Z.

ATTORJEYS v SPRING URGED IGNITABLE ACTUATING ELEMENT BACKGROUND OF THE INVENTION Cartridge-type actuating elements are known wherein a relatively gas deficient propellant charge is remotely ignited to move a piston or a buckling metallic sleeve to bring about or release an actuating or regulating operation. Electric primers are advantageous forremote control.

A piston-cylinder type of actuating element is known wherein the propellant charge will relatively move the two to provide a pushing or pulling action. The charge being ignited on one side of the piston and passing across to exert its pressure on the other side of the piston.

With this type of actuating element, it has been difficult to accurately and securely fix the end positions of the actuating member before and after its movement, particularly outwardly, which is particularly important in rockets wherein it is desirable to prevent movement of the actuating member.

SUMMARY OF THE INVENTION It is an object-of the present invention to avoid the above disadvantages by providing an actuating element with a piston and cylinder housing containing a pyrotechnic charge or delay composition ignitable by a series-connected electric primer, wherein the piston is held in its normal initial position against the pressure ofa spring until the burning of the charge or composition and the spring is correlated to the piston stroke so that after displacement of the piston to its terminal position the spring will still exert a residual pressure thereon.

The pyrotechnic charge or composition may be designed to develop a sufficient amount of heat, but no pressure. This heat may be used to melt a metallic member holding the piston in its initial position against the pressure of the spring. Instead of meltable metallic member, a metallic member, for example a steel disk, may be employed that will directly engage the charge or composition so that it is deformed by and progressively moved into the slag formed by the burning charge or composition, with the piston moving concurrently therewith.

On the other hand, the charge or composition may be designed so that it will burn to produce a pressure sufficient for displacing the piston against the pressure of the spring. In order to prevent subsequent return of the piston from its terminal position after the pressure has been reduced, the spring may be placed behind the piston at its terminal position for preventing return of the piston.

BRIEF DESCRIPTION'OF THE DRAWING Further objects, features and advantages of the present invention will become more clear from the following detailed description of a preferred embodiment taken together with the accompanying drawing, wherein:

FIG. 1 is an axial partial cross-sectional view of an actuating element with an actuating piston that will move inwardly;

FIG. 2 is a similar view of another actuating element with an outwardly moving actuating piston;

FIG. 3 is another embodiment of the FIG. 1 device;

FIG. 4 illustrates another actuating element with an outwardly moving piston; and

FIG. 5 shows another embodiment of the actuating element with an outwardly moving piston.

DETAILED DESCRIPTION OF THE DRAWING V nesium alloy, boron, or the like, or a delay composition known per se. On one axial side of the pyrotechnic charge 3, there is provided a cover disk 4 having a centrally located aperture 5 filled with a primer charge 6 to be electrically ignited by means of the series connected positive pole 7 and current supply lines 8 and 9.' The supporting ring 11 is mounted between the positive pole 7 and the flanged end 10 of the easing 1. The other side of the pyrotechnic charge is covered by means of the closure disk 12 which may consist of Woods metal, or an alloy having a melting temperature of 200C., for example. The disk 12 is securely held in its position by means of the spacer sleeve 13, the supporting ring 14 having a central aperture 15, and the inwardly flanged end 16 of the casing 1. A piston 17 is guidingly disposed within the spacer sleeve 13 constituting an actuating member together with its integral stud or pin 18 on one side and its piston rod 19 on its other side. The outer end 19:: of the piston rod 19 projects through the central aperture 15 of the supporting ring 14. The shoulder 21 at the transition point defining the extension 190 axially abuts against the supporting ring M and the pin 18 axially abuts against the disk 12 to determine the position of the piston 17 which is urged in the downwardly direction of the drawing by means of the compressed helical spring 20 between the piston 17 and the supporting ring 14 The outwardly projecting end of the extension 19a may be suitable connected with the device to be operated by the actuating element.

When current is supplied to the lines 8 and 9, the primer 'charge 6 is ignited to in turn ignite and burn the pyrotechnic charge or delay composition 3, which burning will develop a relatively small amount of or no gas but sufficient heat to melt the central portion of the disk 12 so that the pin 18 will move downwardly into the charge 3 concurrently with movement of the piston 17 and piston rod 19 under the bias of the spring 20 toward the tube 2 until axially abutting the tube 2 at the terminal position of the actuating member 17, 18, 19, 19a; the residual pressure of the spring 20 maintaining this terminal position. Also, it is contemplated that pyrotechnic charge and/or delay composition 3 may be covered with a metallic lamina (not shown), for example of steel, that will not melt but will be pressed into the slag of the burning pyrotechnic charge 3 by the pin 18 acting under the pressure of the spring 20.

In the embodiment shown in FIG. 2, corresponding numerals have been shown for corresponding parts with the appropriate above description with respect to FIG. 1 being applicable. Basically, only the arrangement between the piston 17 and the spring 20 has been changed with respect to FIG. 1; the piston 17 being held by means ofa deformed end 22 of the piston rod 19 securely held in the central aperture 23 of the closure disk 24 covering the pyrotechnic charge or delay composition 3. The heat produced by the burning of the charge 3 will melt the disk 4 or relieve a thin steel disk (not shown), so that the piston 17 and piston rod 19 will be displaced in the direction of the arrow under the influence of the compressed spring 20 until the piston 17 axially abuts the supporting ring 14 at its terminal position wherein it will be held by the residual bias of the still compressed spring 20.

In the embodiment shown in FIG. 3, numerals have been used that correspond with those of FIG. 1 and the above description is equally applicable with respect thereto. However, instead of the flanged ends 10 and 16 of FIG. 1, closure caps or covers 25 and 26 are screwed into the ends of the cylindrical casing or housing 1 of FIG. 3, which construction has the advantage that the assembly of the actuating element a is considerably simplified and defective or spent parts may be replaced. The casing 1 is provided with an annular shoulder 27 for axially fixing, in one direction, 'the' position of the small tube 2 containing therein the pyrotechnic charge 3. In contrast' to FIG. 1, the closure disk 28 of the pyrotechnic charge 3 on one side of the piston 17 is not placed upon the annular end face of the small tube 2, but instead :is provided as a steel disk 7 and fitted precisely into the inside aperture of the small tube 2 directly upon the pyrotechnic charge and/or delay composition 3. Also, in contrast to FIG. 1, the primer charge of the electric primer is disposed within the casing of the igniting primer 7, which works in principle identical to the electric primer of the FIG. 1, device.

In the embodiment of the actuating element shown in FIG. 4, the piston or piston rod 19 has a reduced diameter axial extension 19a with a further reduced diameter stud 30 screwed into the disk or plate 31 that will be used as a control element before and after firing. Prior to firing, the ring spring 20 engages the right-hand shoulder of the actuating member 19 to resiliently retain it in its initial position biased directly against the charge 3; this shoulder being a cam or wedge-type annular surface. On firing, the charge 3 will produce a small amount of gas to exert a pressure upon the actuating element 19 to move it towards the right, as viewed in FIG. 4, so that the actuating member 19 will move through the spring ring 20, which will be radially expanded. After'the actuating member 19 has moved to the right through the spring 20, the spring 20 will radially contract to its original diameter behind the rear abutment surface of the actuating member 19 to retain it in its forward terminal position. The screw cap is provided with an internal portion of increased diameter 29 to allow the above described movement ofthe actuating member to the right and at the same time to define an abutment facing to the left that determines the terminal position of the actuating member 19 with respect to its outward movement.

In the embodiment illustrated in FIG. 5, the actuating member 19, 19a will move outwardly in the direction of the arrow as will the actuating member of the FIG. 4 device. Corresponding numerals have been applied to parts corresponding to those previously described. The actuating member 19, 19a is held in its illustrated initial position against the force of the compressed coil spring 20 by means of the tensioned wire 33 extending through the transverse bore 32 in the journal or stud integral with the actuating member 19, 190 at one end and secured at its other lower end to the casing or housing. The pyrotechnic charge 3 is ignited by means of the electric primer 7 to produce heat sufficient for melting the wire 33 at least at its ends adjacent to the charge 3. When the wire 33 is melted, the spring 20 will move the thus released actuating member 19, 19a forwardly, that is, upwardly with respect to the illustrated position of FIG. 5, until the forwardly facing shoulder of the actuating member engages the rearwardly facing shoulder of the casing at the terminal position where it will be securely held by the residual pressure applied by the still compressed spring 20.

While several preferred embodiments have been specifically described for purposes of illustration, further modifications, embodiments and variations are contemplated, as would be apparent to one with normal skill in'the pertinent technolo- We claim: r

1. An actuating element, comprising: a housing; an actuating member mounted'for relative movement in the direction of actuation with respect to said housing between a normal first position and a second actuated position; a pyrotechnic composition charge within said housing; means for igniting said pyrotechnic charge; a spring operatively mounted biased between said housing and said actuating member in both of said positions; said spring and said pyrotechnic charge constituting at least in part means for securely holding said actuating member in each ofits positions and for moving said actuating member from said first position to said second position in response to ignition of said pyrotechnic charge, said actuating member and said spring are disposed, in alignmennwithin said housing, said housing including fixed opposed abutment surfaces each preventing movement of said actuating member in one direction in each of its two positions, respectively; said securely holding and moving means including a member between said housing and said actuating member holding said actuating member in its first position against the bias of said spring; said member consisting essentially of a material readily meltable at relatively low temperatures substantially below the burning temperature of said pyrotechnic charge and substantially above the normal ambient temperatures; and said spring prevents movement of said actuating member in the other direction from said second position.

2. The actuating element according to claim 1, wherein said securely holding and moving means includes a metallic means engaging said pyrotechnic charge and operatively interposed between said housing and said actuating member to hold said actuating member in its firstposition and being bodily movable into the slag of the burning pyrotechnic charge under the bias of said spring to allow movement of said actuating member.

3. The actuating element according to claim 1. wherein said spring biases said actuating member from said first position to said second position; said securely holding and moving means includes a wire secured between said actuating member and said housing normally holding said actuating member in its first position against the force of said spring; and said wire comprising a material having a relatively low melting temperature substantially lower than the temperature of the burning pyrotechnic mixture and substantially above the normal ambient temperatures to be melted solely by the heat given off from the burning of said pyrotechnic charge to release said actuating member for movement to said second position under the bias of said spring. I

4. The actuating element according to claim 1', wherein said housing includes a tubular casing having screw threads at its opposite ends; a cap screwed into each of said ends and having a central aperture therein; said actuating member extending through the central aperture of one of said caps and electrical supply leads extending through the central aperture of the other of said caps; said igniting means including an electrically actuated primer incircuit with said leads.

5. An actuating element, comprising; a housing; an actuating member mounted for relative movement in the direction of actuation'with respect to said housing between a normal first position and a second actuated position; a pyrotechnic composition charge within said housing; means for igniting said pyrotechnic charge; a spring operatively mounted biased between said housing and said actuating member in both of said positions; said spring and said pyrotechnic charge constituting at least in part means for securely holding said actuating member in each of its positions and for moving said actuating member from said first position to said second position in .response to ignition of said pyrotechnic charge, wherein said housing includes a tubular casing inwardly flanged at its opposite ends to retain said actuating member, said spring, said pyrotechnic charge, said igniting means therein; and wherein said securely holding and moving means includes a member between said housing and said actuating member holding said actuating member in its first position against the bias of said spring; said member consisting essentially of a material readily meltable at relatively low temperatures substantially below the burning temperature of said pyrotechnic charge and substantially above the normal ambient temperatures.

6. An actuating element, comprising: a housing; an actuating member mounted for relative movement in the direction of actuation with respect to said housing between a normal first position and a second actuated position; a pyrotechnic composition charge within said housing; means for igniting said pyrotechnic charge; a spring operatively mounted biased between said housing and said actuating member in both of said positions; said. spring and said pyrotechnic charge constituting at least in part means for securely holding said actuating member in each of its positions and for moving said actuating member from said first position to said second position in response to ignition of said pyrotechnic charge, wherein said actuating member is a piston andsaid housing includes a tubular casing slidably receiving said piston therein, said igniting means including a series-connected electrically ignited primer and wherein said securely holding and moving means includes a metallic member between said housing and said actuating member holding said actuating member in its first position against the bias of said spring; said metallic memberconsisting essentially of a material readily meltable at relatively low temperatures substantially below the burning temperature of said 7. An actuatingelement, comprising: a housing; an actuating member mounted for relative movement in the direction of actuation with respect to said housing between a normal first position and a second actuated position; a pyrotechnic composition charge within said housing; means for igniting said pyrotechnic charge; a spring operatively mounted biased between said housing and said actuating member in both of said positions; said spring and said pyrotechnic charge constituting at least in part means for securely holding said actuat ing member in each of its positions and for moving said actuating member from said first position to said second position in response to ignition of said pyrotechnic charge, wherein said spring resiliently biases said actuating member from said first position to said second position; said securely holding and moving means including a plate immediately adjacent said pyrotechnic charge and blocking movement of said actuating member from said first position to said second position; said plate comprising a material having a relatively low melting temperature substantially below the burning temperature of said pyrotechnic charge and substantially above the normal ambient temperatures to be melted solely by the heat generated by said pyrotechnic charge for releasing said actuating member for movement to said second position under the bias of said spring. 

